1) Field of the Invention
The present invention relates to an ink printer having a print head for ejecting ink onto a recording member, and an inktank, detachable from the print head, for reserving ink to be supplied to the print head therefrom, and to an inktank, and more particularly to a joint part to which the inktank is attached.
2) Description of the Related Art
Recently, ink-jet printers are utilized extensively because the ink-jet printers make printed images of good quality available with less noise. Particularly, many of the inkjet printers that have been developed so far are intended for personal use as they can be made compact in size. Such small-sized printers for personal use are designed so that users themselves are allowed to replace inktanks or ink-jet cartridges integral with print heads to produce a fresh supply of ink. In the case of a replaceable inktank in particular, a fresh supply of ink is procurable at a lower cost and the running cost is reducible accordingly.
With respect to the printer provided with such a replaceable inktank, there have been cases where ink seeps out in the surrounding area of the joint part to which the inktank is attached when the inktank is replaced and problems arising from ink leakage include causing the user to stain his fingers with ink, including ink to drip into the machine proper and so forth.
A method for solving the foregoing problems as disclosed in, for example, Published Unexamined Japanese Patent Application Hei. 3-92356 is to form an ink outlet in the underside of an inktank with a rubber tap through which a metal ink supply needle is injected to pass so as to communicate the rubber tap with an ink flow path to a print head. The ink supply needle thus arranged is rendered resistant to corrosion and the tip of a pipe is sharp-pointed so that it can pass through the rubber tap. Even when the inktank is detached, the ink supply port of the inktank is closed because of the elasticity of the rubber tap to thereby prevent ink from leaking. However, there still exits a problem in that inadvertent handling may cause the user to touch the pointed tip of the pipe, thus inflicting an injury on him. Since the inner diameter of the ink supply needle itself is small, another problem arises from an obstruction to the ink supply in the case where fragments of the rubber tap creep into the inside of the ink supply needle.
A method proposed to solve the foregoing problems, as disclosed in, for example, Published Unexamined Patent Application No. Sho. 50-74341, is to provide an inktank in which a cover plate of rubber having a through-hole is mounted to the leading end of an ink supply port, and the through-hole is sealed with a thin rubber film having a split. Consequently, a liquid guide pipe relatively less pointed can readily be inserted. In this case, however, there still arises a problem that a small amount of ink may leak out of the through-hole and through the split.
Another method for the purpose, as disclosed in, for example, Published Unexamined Japanese Patent Application Nos. Hei. 2-214665, Hei. 6-966, is provided an inktank in which an inktank connection portion is sealed with a sealing member, and a printer connection portion is formed with a rigid porous material, a protruded piece for punching being placed around the porous material. With the inktank, the sealing member of an inktank is broken with the protruded piece for punching when the inktank is attached, and the porous material is fit-pressed against a porous material within the inktank to couple both together. With this arrangement, the leading end portion of an ink supply pipe which is provided with the porous material, is relatively wide and this prevents the pipe from being clogged up. As the protruded piece for punching need not be sharp-pointed so much, there is no fear of injury. Since the inktank is initially sealed with the sealing member, no ink leakage occurs. However, the rigid porous material is always supplied with ink abundantly and a problem arising from the arrangement like this is that the ink thus supplied falls in drops when the inktank is detached.
In recent years, a variety of color ink printers are developed extensively and a single integral print head for the printers is capable of printing multi-color image. In the case of such an integral print head, ink falling in drops as well as ink leakage as described above tends to cause color ink to be mixed up.